1. Field of the Invention
The present invention relates to a control device for an opening/closing member such as a control device for opening/closing a window (hereinafter referred to as “power window device”) used in a vehicle.
2. Description of the Related Art
A power window device is a device for forward rotating and reverse rotating a motor by operating a switch, and raising and lowering a window glass of a door to open/close a window. FIG. 1 shows a block diagram of an electrical configuration of the power window device. A control unit 1 including a CPU controls the opening/closing operation of the window, a motor drive circuit 2 drives a motor 3, a rotary encoder 4 outputs a pulse synchronized with a rotation of the motor 3, a pulse detection circuit 5 detects a pulse output from the rotary encoder 4, a memory 6 is configured by a ROM, a RAM, or the like, and an operation switch 7 operates the opening/closing of the window.
When the operation switch 7 is operated, a window opening/closing command is provided to the control unit 1, and the motor 3 is forward rotated and reverse rotated by the motor drive circuit 2. A window opening/closing mechanism linked with the motor 3 operates through rotation of the motor 3, and opening/closing of the window is performed. The pulse detection circuit 5 detects the pulse output from the rotary encoder 4, and the control unit 1 calculates a rotation speed of the motor and the moved distance of the window based on the detection result, and controls the rotation of the motor 3 via the motor drive circuit 2.
FIG. 2 shows a schematic configuration view of one example of the operation switch 7. The operation switch 7 is configured by an operation knob 71 rotatable in an a-b direction with an axis Q as the center, a rod 72 arranged integrally with the operation knob 71, and a known slide switch 73. The slide switch 73 has an actuator 74, and the operation switch 7 is incorporated in a switch unit 20. A lower end of the rod 72 engages the actuator 74 of the slide switch 73, where the actuator 74 moves in a c-d direction by way of the rod 72 when the operation knob 71 is rotated in the a-b direction, so that a contacting point (not shown) of the slide switch 73 switches according to the moved position.
The operation knob 71 can be switched to each position of automatic close AC, manual close MC, neutral N, manual open MO, and automatic open AO. FIG. 2 shows a state in which the operation knob 71 is at the neutral N position. When the operation knob 71 is rotated by a constant amount in an a direction from such position and positioned at the manual close MC position, a manual closing operation in which the window is closed through manual operation is performed, and when the operation knob 71 is further rotated in the a direction and positioned at the automatic close AC position, the automatic closing operation in which the window is closed through automatic operation is performed. When the operation knob 71 is rotated by a constant amount in a b direction and positioned at the manual open MO position, the manual opening operation in which the window is opened through manual operation is performed, and when the operation knob 71 is further rotated in the b direction and positioned at the automatic open AO position, the automatic opening operation in which the window is opened through automatic operation is performed. A spring (not shown) is arranged in the operation knob 71, so that the operation knob 71 returns to the neutral N position by a force of the spring when the hand is taken off from the rotated operation knob 71.
In the case of manual operation, an operation of closing the window or an operation of opening the window is carried out while the operation knob 71 is being held by hand at the position of manual close MC or manual open MO, and the closing operation or the opening operation of the window stops when the hand is taken off from the operation knob 71 and the knob is returned to the neutral N position. In the case of automatic operation, once the operation knob 71 is rotated to the position of automatic close AC or automatic open AO, the closing operation or the opening operation of the window is thereafter continuously carried out even when the hand is taken off from the operation knob 71 and the operation knob is returned to the neutral N position.
FIG. 3 shows a view of one example of the window opening/closing mechanism arranged on each window of the vehicle. Reference symbol 100 is a window of the vehicle, 101 is a window glass for opening and closing the window 100, and 102 is the window opening/closing mechanism. The window glass 101 rises and lowers by an operation of the window opening/closing mechanism 102, where the window 100 closes by raising the window glass 101 and the window 100 opens by lowering the window glass 101. In the window opening/closing mechanism 102, a supporting member 103 is attached to a lower end of the window glass 101. A first arm 104 has a first end engaging the supporting member 103 and a second end being rotatably supported by the blanket 106, and a second arm 105 having a first end engaging the supporting member 103 and a second end engaging a guide member 107 are provided. The first arm 104 and the second arm 105 are connected at the respective intermediate part by way of a shaft. Reference symbol 3 is the motor described above, and reference symbol 4 is the rotary encoder described above. The rotary encoder 4 is connected to a rotation shaft of the motor 3, and outputs a pulse of the number proportional to a rotation amount of the motor 3. A rotation speed of the motor 3 can be detected by counting a pulse output from the rotary encoder 4 within a predetermined time. Furthermore, the rotation amount of the motor 3 (moved distance of the window glass) can be calculated from an output of the rotary encoder 4.
A pinion 109 is rotatably driven by the motor 3, and a fan shaped gear 110 rotates by gearing with the pinion 109. The gear 110 is fixed to the first arm 104. The motor 3 is rotatable in a forward and reverse direction, where the pinion 109 and the gear 110 are rotated by such rotation in the forward and reverse direction thereby turning the first arm 104 in the forward and reverse direction. Following thereto, the other end of the second arm 105 slides in the lateral direction along a groove of a guide member 107 and the supporting member 103 moves in an up and down direction to raise and lower the window glass 101, thereby opening or closing the window 100.
A function for detecting entrapment of an object when the operation knob 71 is at the automatic close AC position in FIG. 2 and automatic closing operation is performed is provided to the power window device configured as above. In other words, when an object Z gets entrapped in a gap of the window glass 101 while the window 100 is being closed, as shown in FIG. 4, such entrapment is detected, and the closing operation of the window 100 is switched to the opening operation. Since the window 100 automatically closes during the automatic closing operation, an entrapment detection mechanism acts from the necessity of preventing human body from being harmed thereby prohibiting the closing operation of the window 100 when hand, neck, or the like gets entrapped by an accident. In detecting entrapment, the rotation speed of the motor 3, which is an output of the pulse detection circuit 5, is read by the control unit 1, as needed, and a present rotation speed and a past rotation speed are compared to determine the presence of entrapment based on the comparison result (variation in rotation speed). When the object Z is entrapped in the window 100, a load of the motor 3 increases, the rotation speed decreases and the variation in speed increases, where judgment is made that the object Z is entrapped when the variation in speed exceeds a predetermined threshold value. The threshold value is stored in the memory 6 in advance.
In the window opening/closing mechanism 102 shown in FIGS. 3 and 4, the first arm 104 and the second arm 105 configure an X-shaped link mechanism, and a power of the motor 3 is transmitted to the window glass 101 through the link mechanism. The arms configuring the X-shaped link mechanism are hereinafter referred to as “X-arm”. A detailed mechanism of the X-arm is described in Japanese Utility Model Registration Publication No. 2555475 to be hereinafter described. In addition to the X-arm, a single arm configured by only one arm may be used for the window opening/closing mechanism.
When a weather strip (not shown) arranged in a sash of the window 100 contacts the window glass 101 near a fully closed position of the window glass 101, a movement speed of the window glass 101 decreases due to friction generated by such contact. When the movement speed decreases, a variation in speed reduces and becomes lower than the threshold value even if entrapment occurred, and thus entrapping may not be accurately detected.
A power window device is thus disclosed in Japanese Patent Publication No. 2857048 in which a region in which the window moves from a fully opened state to a fully closed state is divided into plurals, a different threshold value is set for every region, and judgment is made that foreign object is entrapped when the load exceeds the corresponding threshold value, thereby correctly making the judgment of entrapment of the foreign object even if the movement speed decreases near the fully closed position of the window glass. A control device for an opening/closing member is disclosed in Japanese Laid-Open Patent Publication no. 2002-327574 in which the rotation speed of the motor is reduced in a predetermined interval near the fully closed position to increase the margin with respect to an entrapment load and prevent mistaken judgment of entrapment caused by friction of the weather strip or the like and in which the output of the motor is increased when the rotation speed becomes lower than or equal to a defined value immediately before the fully closed position to reliably close the opening/closing member.